Flush toilets for domestic use are generally designed to operate using a relatively large volume of water and because of this are not suitable for use in environments in which large volumes of water and/or high capacity waste disposal systems are not available, for example in recreational vehicles, cottages, etc. Low volume flush toilets have therefore been developed for this type of application. The present invention has been devised primarily (but not exclusively) in connection with a toilet of this type.
Generally, low volume flush toilets are designed to operate using to a low pressure flush water supply such as may typically be found in a cottage or recreational vehicle. Portable toilets having flushing systems have also been devised. Typically, a reservoir for flushing liquid is incorporated in the toilet around the bowl and a manually operable pump is provided for dispensing liquid from the reservoir into the bowl.
In neither type of flush toilet is the volume of flush liquid sufficient to empty to a trap such as is conventionally provided at the bowl outlet of a domestic toilet. Normal practice, therefore, is to provide a plain, usually circular opening at the bottom of the toilet bowl and a mechanical sealing mechanism for closing the outlet.